// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CDM_CONTENT_DECRYPTION_MODULE_H_
#define CDM_CONTENT_DECRYPTION_MODULE_H_

#include <type_traits>

#include "content_decryption_module_export.h"
#include "content_decryption_module_proxy.h"

#if defined(_MSC_VER)
typedef unsigned char uint8_t;
typedef unsigned int uint32_t;
typedef int int32_t;
typedef __int64 int64_t;
#else
#include <stdint.h>
#endif

// The version number must be rolled when the exported functions are updated!
// If the CDM and the adapter use different versions of these functions, the
// adapter will fail to load or crash!
#define CDM_MODULE_VERSION 4

// Build the versioned entrypoint name.
// The extra macros are necessary to expand version to an actual value.
#define INITIALIZE_CDM_MODULE \
  BUILD_ENTRYPOINT(InitializeCdmModule, CDM_MODULE_VERSION)
#define BUILD_ENTRYPOINT(name, version) \
  BUILD_ENTRYPOINT_NO_EXPANSION(name, version)
#define BUILD_ENTRYPOINT_NO_EXPANSION(name, version) name##_##version

// Macro to check that |type| does the following:
// 1. is a standard layout.
// 2. is trivial.
// 3. sizeof(type) matches the expected size in bytes. As some types contain
//    pointers, the size is specified for both 32 and 64 bit.
#define CHECK_TYPE(type, size_32, size_64)                           \
  static_assert(std::is_standard_layout<type>(),                     \
                #type " not standard_layout");                       \
  static_assert(std::is_trivial<type>(), #type " not trivial");      \
  static_assert((sizeof(void*) == 4 && sizeof(type) == size_32) ||   \
                    (sizeof(void*) == 8 && sizeof(type) == size_64), \
                #type " size mismatch")

extern "C" {

  CDM_API void INITIALIZE_CDM_MODULE();

  CDM_API void DeinitializeCdmModule();

  // Returns a pointer to the requested CDM Host interface upon success.
  // Returns NULL if the requested CDM Host interface is not supported.
  // The caller should cast the returned pointer to the type matching
  // |host_interface_version|.
  typedef void* (*GetCdmHostFunc)(int host_interface_version, void* user_data);

  // Returns a pointer to the requested CDM upon success.
  // Returns NULL if an error occurs or the requested |cdm_interface_version| or
  // |key_system| is not supported or another error occurs.
  // The caller should cast the returned pointer to the type matching
  // |cdm_interface_version|.
  // Caller retains ownership of arguments and must call Destroy() on the returned
  // object.
  CDM_API void* CreateCdmInstance(int cdm_interface_version,
    const char* key_system,
    uint32_t key_system_size,
    GetCdmHostFunc get_cdm_host_func,
    void* user_data);

  CDM_API const char* GetCdmVersion();

}  // extern "C"

namespace cdm {

  enum Status : uint32_t {
    kSuccess = 0,
    kNeedMoreData,  // Decoder needs more data to produce a decoded frame/sample.
    kNoKey,         // The required decryption key is not available.
    kInitializationError,    // Initialization error.
    kDecryptError,           // Decryption failed.
    kDecodeError,            // Error decoding audio or video.
    kDeferredInitialization  // Decoder is not ready for initialization.
  };
  CHECK_TYPE(Status, 4, 4);

  // Exceptions used by the CDM to reject promises.
  // https://w3c.github.io/encrypted-media/#exceptions
  enum Exception : uint32_t {
    kExceptionTypeError,
    kExceptionNotSupportedError,
    kExceptionInvalidStateError,
    kExceptionQuotaExceededError
  };
  CHECK_TYPE(Exception, 4, 4);

  // The encryption scheme. The definitions are from ISO/IEC 23001-7:2016.
  enum class EncryptionScheme : uint32_t {
    kUnencrypted = 0,
    kCenc,  // 'cenc' subsample encryption using AES-CTR mode.
    kCbcs   // 'cbcs' pattern encryption using AES-CBC mode.
  };
  CHECK_TYPE(EncryptionScheme, 4, 4);

  // The pattern used for pattern encryption. Note that ISO/IEC 23001-7:2016
  // defines each block to be 16-bytes.
  struct Pattern {
    uint32_t crypt_byte_block;  // Count of the encrypted blocks.
    uint32_t skip_byte_block;   // Count of the unencrypted blocks.
  };
  CHECK_TYPE(Pattern, 8, 8);

  enum class ColorRange : uint8_t {
    kInvalid,
    kLimited,  // 709 color range with RGB values ranging from 16 to 235.
    kFull,     // Full RGB color range with RGB values from 0 to 255.
    kDerived   // Range is defined by |transfer_id| and |matrix_id|.
  };
  CHECK_TYPE(ColorRange, 1, 1);

  // Described in ISO 23001-8:2016, section 7. All the IDs are in the range
  // [0, 255] so 8-bit integer is sufficient. An unspecified ColorSpace should be
  // {2, 2, 2, ColorRange::kInvalid}, where value 2 means "Unspecified" for all
  // the IDs, as defined by the spec.
  struct ColorSpace {
    uint8_t primary_id;   // 7.1 colour primaries, table 2
    uint8_t transfer_id;  // 7.2 transfer characteristics, table 3
    uint8_t matrix_id;    // 7.3 matrix coefficients, table 4
    ColorRange range;
  };
  CHECK_TYPE(ColorSpace, 4, 4);

  // Time is defined as the number of seconds since the Epoch
  // (00:00:00 UTC, January 1, 1970), not including any added leap second.
  // Also see Time definition in spec: https://w3c.github.io/encrypted-media/#time
  // Note that Time is defined in millisecond accuracy in the spec but in second
  // accuracy here.
  typedef double Time;

  // An input buffer can be split into several continuous subsamples.
  // A SubsampleEntry specifies the number of clear and cipher bytes in each
  // subsample. For example, the following buffer has three subsamples:
  //
  // |<----- subsample1 ----->|<----- subsample2 ----->|<----- subsample3 ----->|
  // |   clear1   |  cipher1  |  clear2  |   cipher2   | clear3 |    cipher3    |
  //
  // For decryption, all of the cipher bytes in a buffer should be concatenated
  // (in the subsample order) into a single logical stream. The clear bytes should
  // not be considered as part of decryption.
  //
  // Stream to decrypt:   |  cipher1  |   cipher2   |    cipher3    |
  // Decrypted stream:    | decrypted1|  decrypted2 |   decrypted3  |
  //
  // After decryption, the decrypted bytes should be copied over the position
  // of the corresponding cipher bytes in the original buffer to form the output
  // buffer. Following the above example, the decrypted buffer should be:
  //
  // |<----- subsample1 ----->|<----- subsample2 ----->|<----- subsample3 ----->|
  // |   clear1   | decrypted1|  clear2  |  decrypted2 | clear3 |   decrypted3  |
  //
  struct SubsampleEntry {
    uint32_t clear_bytes;
    uint32_t cipher_bytes;
  };
  CHECK_TYPE(SubsampleEntry, 8, 8);

  // Represents an input buffer to be decrypted (and possibly decoded). It does
  // not own any pointers in this struct. If |iv_size| = 0, the data is
  // unencrypted.
  // Deprecated: New CDM implementations should use InputBuffer_2.
  struct InputBuffer_1 {
    const uint8_t* data;  // Pointer to the beginning of the input data.
    uint32_t data_size;   // Size (in bytes) of |data|.

    const uint8_t* key_id;  // Key ID to identify the decryption key.
    uint32_t key_id_size;   // Size (in bytes) of |key_id|.

    const uint8_t* iv;  // Initialization vector.
    uint32_t iv_size;   // Size (in bytes) of |iv|.

    const struct SubsampleEntry* subsamples;
    uint32_t num_subsamples;  // Number of subsamples in |subsamples|.

    int64_t timestamp;  // Presentation timestamp in microseconds.
  };
  CHECK_TYPE(InputBuffer_1, 40, 72);

  // Represents an input buffer to be decrypted (and possibly decoded). It does
  // not own any pointers in this struct. If |encryption_scheme| = kUnencrypted,
  // the data is unencrypted.
  // Note that this struct is organized so that sizeof(InputBuffer_2)
  // equals the sum of sizeof() all members in both 32-bit and 64-bit compiles.
  // Padding has been added to keep the fields aligned.
  struct InputBuffer_2 {
    const uint8_t* data;  // Pointer to the beginning of the input data.
    uint32_t data_size;   // Size (in bytes) of |data|.

    EncryptionScheme encryption_scheme;

    const uint8_t* key_id;  // Key ID to identify the decryption key.
    uint32_t key_id_size;   // Size (in bytes) of |key_id|.
    uint32_t : 32;          // Padding.

               const uint8_t* iv;  // Initialization vector.
               uint32_t iv_size;   // Size (in bytes) of |iv|.
               uint32_t : 32;      // Padding.

                          const struct SubsampleEntry* subsamples;
                          uint32_t num_subsamples;  // Number of subsamples in |subsamples|.
                          uint32_t : 32;            // Padding.

                                                    // |pattern| is required if |encryption_scheme| specifies pattern encryption.
                                     Pattern pattern;

                                     int64_t timestamp;  // Presentation timestamp in microseconds.
  };
  CHECK_TYPE(InputBuffer_2, 64, 80);

  enum AudioCodec : uint32_t { kUnknownAudioCodec = 0, kCodecVorbis, kCodecAac };
  CHECK_TYPE(AudioCodec, 4, 4);

  // Deprecated: New CDM implementations should use AudioDecoderConfig_2.
  struct AudioDecoderConfig_1 {
    AudioCodec codec;
    int32_t channel_count;
    int32_t bits_per_channel;
    int32_t samples_per_second;

    // Optional byte data required to initialize audio decoders, such as the
    // vorbis setup header.
    uint8_t* extra_data;
    uint32_t extra_data_size;
  };
  CHECK_TYPE(AudioDecoderConfig_1, 24, 32);

  struct AudioDecoderConfig_2 {
    AudioCodec codec;
    int32_t channel_count;
    int32_t bits_per_channel;
    int32_t samples_per_second;

    // Optional byte data required to initialize audio decoders, such as the
    // vorbis setup header.
    uint8_t* extra_data;
    uint32_t extra_data_size;

    // Encryption scheme.
    EncryptionScheme encryption_scheme;
  };
  CHECK_TYPE(AudioDecoderConfig_2, 28, 32);

  // Supported sample formats for AudioFrames.
  enum AudioFormat : uint32_t {
    kUnknownAudioFormat = 0,  // Unknown format value. Used for error reporting.
    kAudioFormatU8,           // Interleaved unsigned 8-bit w/ bias of 128.
    kAudioFormatS16,          // Interleaved signed 16-bit.
    kAudioFormatS32,          // Interleaved signed 32-bit.
    kAudioFormatF32,          // Interleaved float 32-bit.
    kAudioFormatPlanarS16,    // Signed 16-bit planar.
    kAudioFormatPlanarF32,    // Float 32-bit planar.
  };
  CHECK_TYPE(AudioFormat, 4, 4);

  // Surface formats based on FOURCC labels, see: http://www.fourcc.org/yuv.php
  // Values are chosen to be consistent with Chromium's VideoPixelFormat values.
  enum VideoFormat : uint32_t {
    kUnknownVideoFormat = 0,  // Unknown format value. Used for error reporting.
    kYv12 = 1,                // 12bpp YVU planar 1x1 Y, 2x2 VU samples.
    kI420 = 2,                // 12bpp YUV planar 1x1 Y, 2x2 UV samples.

                              // In the following formats, each sample uses 16-bit in storage, while the
                              // sample value is stored in the least significant N bits where N is
                              // specified by the number after "P". For example, for YUV420P9, each Y, U,
                              // and V sample is stored in the least significant 9 bits in a 2-byte block.
                              kYUV420P9 = 16,
                              kYUV420P10 = 17,
                              kYUV422P9 = 18,
                              kYUV422P10 = 19,
                              kYUV444P9 = 20,
                              kYUV444P10 = 21,
                              kYUV420P12 = 22,
                              kYUV422P12 = 23,
                              kYUV444P12 = 24,
  };
  CHECK_TYPE(VideoFormat, 4, 4);

  struct Size {
    int32_t width;
    int32_t height;
  };
  CHECK_TYPE(Size, 8, 8);

  enum VideoCodec : uint32_t {
    kUnknownVideoCodec = 0,
    kCodecVp8,
    kCodecH264,
    kCodecVp9,
    kCodecAv1
  };
  CHECK_TYPE(VideoCodec, 4, 4);

  enum VideoCodecProfile : uint32_t {
    kUnknownVideoCodecProfile = 0,
    kProfileNotNeeded,
    kH264ProfileBaseline,
    kH264ProfileMain,
    kH264ProfileExtended,
    kH264ProfileHigh,
    kH264ProfileHigh10,
    kH264ProfileHigh422,
    kH264ProfileHigh444Predictive,
    // VP9 Profiles are only passed in starting from CDM_9.
    kVP9Profile0,
    kVP9Profile1,
    kVP9Profile2,
    kVP9Profile3,
    kAv1ProfileMain,
    kAv1ProfileHigh,
    kAv1ProfilePro
  };
  CHECK_TYPE(VideoCodecProfile, 4, 4);

  // Deprecated: New CDM implementations should use VideoDecoderConfig_3.
  struct VideoDecoderConfig_1 {
    VideoCodec codec;
    VideoCodecProfile profile;
    VideoFormat format;

    // Width and height of video frame immediately post-decode. Not all pixels
    // in this region are valid.
    Size coded_size;

    // Optional byte data required to initialize video decoders, such as H.264
    // AAVC data.
    uint8_t* extra_data;
    uint32_t extra_data_size;
  };
  CHECK_TYPE(VideoDecoderConfig_1, 28, 40);

  // Deprecated: New CDM implementations should use VideoDecoderConfig_3.
  // Note that this struct is organized so that sizeof(VideoDecoderConfig_2)
  // equals the sum of sizeof() all members in both 32-bit and 64-bit compiles.
  // Padding has been added to keep the fields aligned.
  struct VideoDecoderConfig_2 {
    VideoCodec codec;
    VideoCodecProfile profile;
    VideoFormat format;
    uint32_t : 32;  // Padding.

                    // Width and height of video frame immediately post-decode. Not all pixels
                    // in this region are valid.
               Size coded_size;

               // Optional byte data required to initialize video decoders, such as H.264
               // AAVC data.
               uint8_t* extra_data;
               uint32_t extra_data_size;

               // Encryption scheme.
               EncryptionScheme encryption_scheme;
  };
  CHECK_TYPE(VideoDecoderConfig_2, 36, 40);

  struct VideoDecoderConfig_3 {
    VideoCodec codec;
    VideoCodecProfile profile;
    VideoFormat format;
    ColorSpace color_space;

    // Width and height of video frame immediately post-decode. Not all pixels
    // in this region are valid.
    Size coded_size;

    // Optional byte data required to initialize video decoders, such as H.264
    // AAVC data.
    uint8_t* extra_data;
    uint32_t extra_data_size;

    EncryptionScheme encryption_scheme;
  };
  CHECK_TYPE(VideoDecoderConfig_3, 36, 40);

  enum StreamType : uint32_t { kStreamTypeAudio = 0, kStreamTypeVideo = 1 };
  CHECK_TYPE(StreamType, 4, 4);

  // Structure provided to ContentDecryptionModule::OnPlatformChallengeResponse()
  // after a platform challenge was initiated via Host::SendPlatformChallenge().
  // All values will be NULL / zero in the event of a challenge failure.
  struct PlatformChallengeResponse {
    // |challenge| provided during Host::SendPlatformChallenge() combined with
    // nonce data and signed with the platform's private key.
    const uint8_t* signed_data;
    uint32_t signed_data_length;

    // RSASSA-PKCS1-v1_5-SHA256 signature of the |signed_data| block.
    const uint8_t* signed_data_signature;
    uint32_t signed_data_signature_length;

    // X.509 device specific certificate for the |service_id| requested.
    const uint8_t* platform_key_certificate;
    uint32_t platform_key_certificate_length;
  };
  CHECK_TYPE(PlatformChallengeResponse, 24, 48);

  // The current status of the associated key. The valid types are defined in the
  // spec: https://w3c.github.io/encrypted-media/#idl-def-MediaKeyStatus
  enum KeyStatus : uint32_t {
    kUsable = 0,
    kInternalError = 1,
    kExpired = 2,
    kOutputRestricted = 3,
    kOutputDownscaled = 4,
    kStatusPending = 5,
    kReleased = 6
  };
  CHECK_TYPE(KeyStatus, 4, 4);

  // Used when passing arrays of key information. Does not own the referenced
  // data. |system_code| is an additional error code for unusable keys and
  // should be 0 when |status| == kUsable.
  struct KeyInformation {
    const uint8_t* key_id;
    uint32_t key_id_size;
    KeyStatus status;
    uint32_t system_code;
  };
  CHECK_TYPE(KeyInformation, 16, 24);

  // Supported output protection methods for use with EnableOutputProtection() and
  // returned by OnQueryOutputProtectionStatus().
  enum OutputProtectionMethods : uint32_t {
    kProtectionNone = 0,
    kProtectionHDCP = 1 << 0
  };
  CHECK_TYPE(OutputProtectionMethods, 4, 4);

  // Connected output link types returned by OnQueryOutputProtectionStatus().
  enum OutputLinkTypes : uint32_t {
    kLinkTypeNone = 0,
    kLinkTypeUnknown = 1 << 0,
    kLinkTypeInternal = 1 << 1,
    kLinkTypeVGA = 1 << 2,
    kLinkTypeHDMI = 1 << 3,
    kLinkTypeDVI = 1 << 4,
    kLinkTypeDisplayPort = 1 << 5,
    kLinkTypeNetwork = 1 << 6
  };
  CHECK_TYPE(OutputLinkTypes, 4, 4);

  // Result of the QueryOutputProtectionStatus() call.
  enum QueryResult : uint32_t { kQuerySucceeded = 0, kQueryFailed };
  CHECK_TYPE(QueryResult, 4, 4);

  // The Initialization Data Type. The valid types are defined in the spec:
  // https://w3c.github.io/encrypted-media/format-registry/initdata/index.html#registry
  enum InitDataType : uint32_t { kCenc = 0, kKeyIds = 1, kWebM = 2 };
  CHECK_TYPE(InitDataType, 4, 4);

  // The type of session to create. The valid types are defined in the spec:
  // https://w3c.github.io/encrypted-media/#idl-def-SessionType
  enum SessionType : uint32_t {
    kTemporary = 0,
    kPersistentLicense = 1,
    kPersistentUsageRecord = 2
  };
  CHECK_TYPE(SessionType, 4, 4);

  // The type of the message event.  The valid types are defined in the spec:
  // https://w3c.github.io/encrypted-media/#idl-def-MediaKeyMessageType
  enum MessageType : uint32_t {
    kLicenseRequest = 0,
    kLicenseRenewal = 1,
    kLicenseRelease = 2,
    // Only supported by Host_10 and later. On Host_9 and earlier, it's undefined
    // behavior. For example, the host can drop the message or send it using
    // other message type.
    kIndividualizationRequest = 3
  };
  CHECK_TYPE(MessageType, 4, 4);

  enum HdcpVersion : uint32_t {
    kHdcpVersionNone,
    kHdcpVersion1_0,
    kHdcpVersion1_1,
    kHdcpVersion1_2,
    kHdcpVersion1_3,
    kHdcpVersion1_4,
    kHdcpVersion2_0,
    kHdcpVersion2_1,
    kHdcpVersion2_2,
    kHdcpVersion2_3
  };
  CHECK_TYPE(HdcpVersion, 4, 4);

  struct Policy {
    HdcpVersion min_hdcp_version;
  };
  CHECK_TYPE(Policy, 4, 4);

  // Represents a buffer created by Allocator implementations.
  class CDM_CLASS_API Buffer {
  public:
    // Destroys the buffer in the same context as it was created.
    virtual void Destroy() = 0;

    virtual uint32_t Capacity() const = 0;
    virtual uint8_t* Data() = 0;
    virtual void SetSize(uint32_t size) = 0;
    virtual uint32_t Size() const = 0;

  protected:
    Buffer() {}
    virtual ~Buffer() {}

  private:
    Buffer(const Buffer&);
    void operator=(const Buffer&);
  };

  // Represents a decrypted block that has not been decoded.
  class CDM_CLASS_API DecryptedBlock {
  public:
    virtual void SetDecryptedBuffer(Buffer* buffer) = 0;
    virtual Buffer* DecryptedBuffer() = 0;

    // TODO(tomfinegan): Figure out if timestamp is really needed. If it is not,
    // we can just pass Buffer pointers around.
    virtual void SetTimestamp(int64_t timestamp) = 0;
    virtual int64_t Timestamp() const = 0;

  protected:
    DecryptedBlock() {}
    virtual ~DecryptedBlock() {}
  };

  enum VideoPlane : uint32_t {
    kYPlane = 0,
    kUPlane = 1,
    kVPlane = 2,
    kMaxPlanes = 3,
  };
  CHECK_TYPE(VideoPlane, 4, 4);

  class CDM_CLASS_API VideoFrame {
  public:
    virtual void SetFormat(VideoFormat format) = 0;
    virtual VideoFormat Format() const = 0;

    virtual void SetSize(cdm::Size size) = 0;
    virtual cdm::Size Size() const = 0;

    virtual void SetFrameBuffer(Buffer* frame_buffer) = 0;
    virtual Buffer* FrameBuffer() = 0;

    virtual void SetPlaneOffset(VideoPlane plane, uint32_t offset) = 0;
    virtual uint32_t PlaneOffset(VideoPlane plane) = 0;

    virtual void SetStride(VideoPlane plane, uint32_t stride) = 0;
    virtual uint32_t Stride(VideoPlane plane) = 0;

    // Sets and gets the presentation timestamp which is in microseconds.
    virtual void SetTimestamp(int64_t timestamp) = 0;
    virtual int64_t Timestamp() const = 0;

  protected:
    VideoFrame() {}
    virtual ~VideoFrame() {}
  };

  // Represents a decoded video frame. The CDM should call the interface methods
  // to set the frame attributes. See DecryptAndDecodeFrame().
  class CDM_CLASS_API VideoFrame_2 {
  public:
    virtual void SetFormat(VideoFormat format) = 0;
    virtual void SetSize(cdm::Size size) = 0;
    virtual void SetFrameBuffer(Buffer* frame_buffer) = 0;
    virtual void SetPlaneOffset(VideoPlane plane, uint32_t offset) = 0;
    virtual void SetStride(VideoPlane plane, uint32_t stride) = 0;
    // Sets the presentation timestamp which is in microseconds.
    virtual void SetTimestamp(int64_t timestamp) = 0;
    virtual void SetColorSpace(ColorSpace color_space) = 0;

  protected:
    VideoFrame_2() {}
    virtual ~VideoFrame_2() {}
  };

  // Represents decrypted and decoded audio frames. AudioFrames can contain
  // multiple audio output buffers, which are serialized into this format:
  //
  // |<------------------- serialized audio buffer ------------------->|
  // | int64_t timestamp | int64_t length | length bytes of audio data |
  //
  // For example, with three audio output buffers, the AudioFrames will look
  // like this:
  //
  // |<----------------- AudioFrames ------------------>|
  // | audio buffer 0 | audio buffer 1 | audio buffer 2 |
  class CDM_CLASS_API AudioFrames {
  public:
    virtual void SetFrameBuffer(Buffer* buffer) = 0;
    virtual Buffer* FrameBuffer() = 0;

    // The CDM must call this method, providing a valid format, when providing
    // frame buffers. Planar data should be stored end to end; e.g.,
    // |ch1 sample1||ch1 sample2|....|ch1 sample_last||ch2 sample1|...
    virtual void SetFormat(AudioFormat format) = 0;
    virtual AudioFormat Format() const = 0;

  protected:
    AudioFrames() {}
    virtual ~AudioFrames() {}
  };

  // FileIO interface provides a way for the CDM to store data in a file in
  // persistent storage. This interface aims only at providing basic read/write
  // capabilities and should not be used as a full fledged file IO API.
  // Each CDM and origin (e.g. HTTPS, "foo.example.com", 443) combination has
  // its own persistent storage. All instances of a given CDM associated with a
  // given origin share the same persistent storage.
  // Note to implementors of this interface:
  // Per-origin storage and the ability for users to clear it are important.
  // See http://www.w3.org/TR/encrypted-media/#privacy-storedinfo.
  class CDM_CLASS_API FileIO {
  public:
    // Opens the file with |file_name| for read and write.
    // FileIOClient::OnOpenComplete() will be called after the opening
    // operation finishes.
    // - When the file is opened by a CDM instance, it will be classified as "in
    //   use". In this case other CDM instances in the same domain may receive
    //   kInUse status when trying to open it.
    // - |file_name| must only contain letters (A-Za-z), digits(0-9), or "._-".
    //   It must not start with an underscore ('_'), and must be at least 1
    //   character and no more than 256 characters long.
    virtual void Open(const char* file_name, uint32_t file_name_size) = 0;

    // Reads the contents of the file. FileIOClient::OnReadComplete() will be
    // called with the read status. Read() should not be called if a previous
    // Read() or Write() call is still pending; otherwise OnReadComplete() will
    // be called with kInUse.
    virtual void Read() = 0;

    // Writes |data_size| bytes of |data| into the file.
    // FileIOClient::OnWriteComplete() will be called with the write status.
    // All existing contents in the file will be overwritten. Calling Write() with
    // NULL |data| will clear all contents in the file. Write() should not be
    // called if a previous Write() or Read() call is still pending; otherwise
    // OnWriteComplete() will be called with kInUse.
    virtual void Write(const uint8_t* data, uint32_t data_size) = 0;

    // Closes the file if opened, destroys this FileIO object and releases any
    // resources allocated. The CDM must call this method when it finished using
    // this object. A FileIO object must not be used after Close() is called.
    virtual void Close() = 0;

  protected:
    FileIO() {}
    virtual ~FileIO() {}
  };

  // Responses to FileIO calls. All responses will be called asynchronously.
  // When kError is returned, the FileIO object could be in an error state. All
  // following calls (other than Close()) could return kError. The CDM should
  // still call Close() to destroy the FileIO object.
  class CDM_CLASS_API FileIOClient {
  public:
    enum class Status : uint32_t { kSuccess = 0, kInUse, kError };

    // Response to a FileIO::Open() call with the open |status|.
    virtual void OnOpenComplete(Status status) = 0;

    // Response to a FileIO::Read() call to provide |data_size| bytes of |data|
    // read from the file.
    // - kSuccess indicates that all contents of the file has been successfully
    //   read. In this case, 0 |data_size| means that the file is empty.
    // - kInUse indicates that there are other read/write operations pending.
    // - kError indicates read failure, e.g. the storage is not open or cannot be
    //   fully read.
    virtual void OnReadComplete(Status status,
      const uint8_t* data,
      uint32_t data_size) = 0;

    // Response to a FileIO::Write() call.
    // - kSuccess indicates that all the data has been written into the file
    //   successfully.
    // - kInUse indicates that there are other read/write operations pending.
    // - kError indicates write failure, e.g. the storage is not open or cannot be
    //   fully written. Upon write failure, the contents of the file should be
    //   regarded as corrupt and should not used.
    virtual void OnWriteComplete(Status status) = 0;

  protected:
    FileIOClient() {}
    virtual ~FileIOClient() {}
  };

  class CDM_CLASS_API Host_9;
  class CDM_CLASS_API Host_10;
  class CDM_CLASS_API Host_11;

  // ContentDecryptionModule interface that all CDMs need to implement.
  // The interface is versioned for backward compatibility.
  // Note: ContentDecryptionModule implementations must use the allocator
  // provided in CreateCdmInstance() to allocate any Buffer that needs to
  // be passed back to the caller. Implementations must call Buffer::Destroy()
  // when a Buffer is created that will never be returned to the caller.
  class CDM_CLASS_API ContentDecryptionModule_9 {
  public:
    static const int kVersion = 9;
    typedef Host_9 Host;

    // Initializes the CDM instance, providing information about permitted
    // functionalities.
    // If |allow_distinctive_identifier| is false, messages from the CDM,
    // such as message events, must not contain a Distinctive Identifier,
    // even in an encrypted form.
    // If |allow_persistent_state| is false, the CDM must not attempt to
    // persist state. Calls to CreateFileIO() will fail.
    virtual void Initialize(bool allow_distinctive_identifier,
      bool allow_persistent_state) = 0;

    // Gets the key status if the CDM has a hypothetical key with the |policy|.
    // The CDM must respond by calling either Host::OnResolveKeyStatusPromise()
    // with the result key status or Host::OnRejectPromise() if an unexpected
    // error happened or this method is not supported.
    virtual void GetStatusForPolicy(uint32_t promise_id,
      const Policy& policy) = 0;

    // SetServerCertificate(), CreateSessionAndGenerateRequest(), LoadSession(),
    // UpdateSession(), CloseSession(), and RemoveSession() all accept a
    // |promise_id|, which must be passed to the completion Host method
    // (e.g. Host::OnResolveNewSessionPromise()).

    // Provides a server certificate to be used to encrypt messages to the
    // license server. The CDM must respond by calling either
    // Host::OnResolvePromise() or Host::OnRejectPromise().
    virtual void SetServerCertificate(uint32_t promise_id,
      const uint8_t* server_certificate_data,
      uint32_t server_certificate_data_size) = 0;

    // Creates a session given |session_type|, |init_data_type|, and |init_data|.
    // The CDM must respond by calling either Host::OnResolveNewSessionPromise()
    // or Host::OnRejectPromise().
    virtual void CreateSessionAndGenerateRequest(uint32_t promise_id,
      SessionType session_type,
      InitDataType init_data_type,
      const uint8_t* init_data,
      uint32_t init_data_size) = 0;

    // Loads the session of type |session_type| specified by |session_id|.
    // The CDM must respond by calling either Host::OnResolveNewSessionPromise()
    // or Host::OnRejectPromise(). If the session is not found, call
    // Host::OnResolveNewSessionPromise() with session_id = NULL.
    virtual void LoadSession(uint32_t promise_id,
      SessionType session_type,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Updates the session with |response|. The CDM must respond by calling
    // either Host::OnResolvePromise() or Host::OnRejectPromise().
    virtual void UpdateSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size,
      const uint8_t* response,
      uint32_t response_size) = 0;

    // Requests that the CDM close the session. The CDM must respond by calling
    // either Host::OnResolvePromise() or Host::OnRejectPromise() when the request
    // has been processed. This may be before the session is closed. Once the
    // session is closed, Host::OnSessionClosed() must also be called.
    virtual void CloseSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Removes any stored session data associated with this session. Will only be
    // called for persistent sessions. The CDM must respond by calling either
    // Host::OnResolvePromise() or Host::OnRejectPromise() when the request has
    // been processed.
    virtual void RemoveSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Performs scheduled operation with |context| when the timer fires.
    virtual void TimerExpired(void* context) = 0;

    // Decrypts the |encrypted_buffer|.
    //
    // Returns kSuccess if decryption succeeded, in which case the callee
    // should have filled the |decrypted_buffer| and passed the ownership of
    // |data| in |decrypted_buffer| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kDecryptError if any other error happened.
    // If the return value is not kSuccess, |decrypted_buffer| should be ignored
    // by the caller.
    virtual Status Decrypt(const InputBuffer_1& encrypted_buffer,
      DecryptedBlock* decrypted_buffer) = 0;

    // Initializes the CDM audio decoder with |audio_decoder_config|. This
    // function must be called before DecryptAndDecodeSamples() is called.
    //
    // Returns kSuccess if the |audio_decoder_config| is supported and the CDM
    // audio decoder is successfully initialized.
    // Returns kInitializationError if |audio_decoder_config| is not supported.
    // The CDM may still be able to do Decrypt().
    // Returns kDeferredInitialization if the CDM is not ready to initialize the
    // decoder at this time. Must call Host::OnDeferredInitializationDone() once
    // initialization is complete.
    virtual Status InitializeAudioDecoder(
      const AudioDecoderConfig_1& audio_decoder_config) = 0;

    // Initializes the CDM video decoder with |video_decoder_config|. This
    // function must be called before DecryptAndDecodeFrame() is called.
    //
    // Returns kSuccess if the |video_decoder_config| is supported and the CDM
    // video decoder is successfully initialized.
    // Returns kInitializationError if |video_decoder_config| is not supported.
    // The CDM may still be able to do Decrypt().
    // Returns kDeferredInitialization if the CDM is not ready to initialize the
    // decoder at this time. Must call Host::OnDeferredInitializationDone() once
    // initialization is complete.
    virtual Status InitializeVideoDecoder(
      const VideoDecoderConfig_1& video_decoder_config) = 0;

    // De-initializes the CDM decoder and sets it to an uninitialized state. The
    // caller can initialize the decoder again after this call to re-initialize
    // it. This can be used to reconfigure the decoder if the configuration
    // changes.
    virtual void DeinitializeDecoder(StreamType decoder_type) = 0;

    // Resets the CDM decoder to an initialized clean state. All internal buffers
    // MUST be flushed.
    virtual void ResetDecoder(StreamType decoder_type) = 0;

    // Decrypts the |encrypted_buffer| and decodes the decrypted buffer into a
    // |video_frame|. Upon end-of-stream, the caller should call this function
    // repeatedly with empty |encrypted_buffer| (|data| == NULL) until
    // kNeedMoreData is returned.
    //
    // Returns kSuccess if decryption and decoding both succeeded, in which case
    // the callee will have filled the |video_frame| and passed the ownership of
    // |frame_buffer| in |video_frame| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kNeedMoreData if more data was needed by the decoder to generate
    // a decoded frame (e.g. during initialization and end-of-stream).
    // Returns kDecryptError if any decryption error happened.
    // Returns kDecodeError if any decoding error happened.
    // If the return value is not kSuccess, |video_frame| should be ignored by
    // the caller.
    virtual Status DecryptAndDecodeFrame(const InputBuffer_1& encrypted_buffer,
      VideoFrame* video_frame) = 0;

    // Decrypts the |encrypted_buffer| and decodes the decrypted buffer into
    // |audio_frames|. Upon end-of-stream, the caller should call this function
    // repeatedly with empty |encrypted_buffer| (|data| == NULL) until only empty
    // |audio_frames| is produced.
    //
    // Returns kSuccess if decryption and decoding both succeeded, in which case
    // the callee will have filled |audio_frames| and passed the ownership of
    // |data| in |audio_frames| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kNeedMoreData if more data was needed by the decoder to generate
    // audio samples (e.g. during initialization and end-of-stream).
    // Returns kDecryptError if any decryption error happened.
    // Returns kDecodeError if any decoding error happened.
    // If the return value is not kSuccess, |audio_frames| should be ignored by
    // the caller.
    virtual Status DecryptAndDecodeSamples(const InputBuffer_1& encrypted_buffer,
      AudioFrames* audio_frames) = 0;

    // Called by the host after a platform challenge was initiated via
    // Host::SendPlatformChallenge().
    virtual void OnPlatformChallengeResponse(
      const PlatformChallengeResponse& response) = 0;

    // Called by the host after a call to Host::QueryOutputProtectionStatus(). The
    // |link_mask| is a bit mask of OutputLinkTypes and |output_protection_mask|
    // is a bit mask of OutputProtectionMethods. If |result| is kQueryFailed,
    // then |link_mask| and |output_protection_mask| are undefined and should
    // be ignored.
    virtual void OnQueryOutputProtectionStatus(
      QueryResult result,
      uint32_t link_mask,
      uint32_t output_protection_mask) = 0;

    // Called by the host after a call to Host::RequestStorageId(). If the
    // version of the storage ID requested is available, |storage_id| and
    // |storage_id_size| are set appropriately. |version| will be the same as
    // what was requested, unless 0 (latest) was requested, in which case
    // |version| will be the actual version number for the |storage_id| returned.
    // If the requested version is not available, null/zero will be provided as
    // |storage_id| and |storage_id_size|, respectively, and |version| should be
    // ignored.
    virtual void OnStorageId(uint32_t version,
      const uint8_t* storage_id,
      uint32_t storage_id_size) = 0;

    // Destroys the object in the same context as it was created.
    virtual void Destroy() = 0;

  protected:
    ContentDecryptionModule_9() {}
    virtual ~ContentDecryptionModule_9() {}
  };

  // ContentDecryptionModule interface that all CDMs need to implement.
  // The interface is versioned for backward compatibility.
  // Note: ContentDecryptionModule implementations must use the allocator
  // provided in CreateCdmInstance() to allocate any Buffer that needs to
  // be passed back to the caller. Implementations must call Buffer::Destroy()
  // when a Buffer is created that will never be returned to the caller.
  class CDM_CLASS_API ContentDecryptionModule_10 {
  public:
    static const int kVersion = 10;
    static const bool kIsStable = true;
    typedef Host_10 Host;

    // Initializes the CDM instance, providing information about permitted
    // functionalities. The CDM must respond by calling Host::OnInitialized()
    // with whether the initialization succeeded. No other calls will be made by
    // the host before Host::OnInitialized() returns.
    // If |allow_distinctive_identifier| is false, messages from the CDM,
    // such as message events, must not contain a Distinctive Identifier,
    // even in an encrypted form.
    // If |allow_persistent_state| is false, the CDM must not attempt to
    // persist state. Calls to CreateFileIO() will fail.
    // If |use_hw_secure_codecs| is true, the CDM must ensure the decryption key
    // and video buffers (compressed and uncompressed) are securely protected by
    // hardware.
    virtual void Initialize(bool allow_distinctive_identifier,
      bool allow_persistent_state,
      bool use_hw_secure_codecs) = 0;

    // Gets the key status if the CDM has a hypothetical key with the |policy|.
    // The CDM must respond by calling either Host::OnResolveKeyStatusPromise()
    // with the result key status or Host::OnRejectPromise() if an unexpected
    // error happened or this method is not supported.
    virtual void GetStatusForPolicy(uint32_t promise_id,
      const Policy& policy) = 0;

    // SetServerCertificate(), CreateSessionAndGenerateRequest(), LoadSession(),
    // UpdateSession(), CloseSession(), and RemoveSession() all accept a
    // |promise_id|, which must be passed to the completion Host method
    // (e.g. Host::OnResolveNewSessionPromise()).

    // Provides a server certificate to be used to encrypt messages to the
    // license server. The CDM must respond by calling either
    // Host::OnResolvePromise() or Host::OnRejectPromise().
    // If the CDM does not support server certificates, the promise should be
    // rejected with kExceptionNotSupportedError. If |server_certificate_data|
    // is empty, reject with kExceptionTypeError. Any other error should be
    // rejected with kExceptionInvalidStateError or kExceptionQuotaExceededError.
    // TODO(crbug.com/796417): Add support for the promise to return true or
    // false, rather than using kExceptionNotSupportedError to mean false.
    virtual void SetServerCertificate(uint32_t promise_id,
      const uint8_t* server_certificate_data,
      uint32_t server_certificate_data_size) = 0;

    // Creates a session given |session_type|, |init_data_type|, and |init_data|.
    // The CDM must respond by calling either Host::OnResolveNewSessionPromise()
    // or Host::OnRejectPromise().
    virtual void CreateSessionAndGenerateRequest(uint32_t promise_id,
      SessionType session_type,
      InitDataType init_data_type,
      const uint8_t* init_data,
      uint32_t init_data_size) = 0;

    // Loads the session of type |session_type| specified by |session_id|.
    // The CDM must respond by calling either Host::OnResolveNewSessionPromise()
    // or Host::OnRejectPromise(). If the session is not found, call
    // Host::OnResolveNewSessionPromise() with session_id = NULL.
    virtual void LoadSession(uint32_t promise_id,
      SessionType session_type,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Updates the session with |response|. The CDM must respond by calling
    // either Host::OnResolvePromise() or Host::OnRejectPromise().
    virtual void UpdateSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size,
      const uint8_t* response,
      uint32_t response_size) = 0;

    // Requests that the CDM close the session. The CDM must respond by calling
    // either Host::OnResolvePromise() or Host::OnRejectPromise() when the request
    // has been processed. This may be before the session is closed. Once the
    // session is closed, Host::OnSessionClosed() must also be called.
    virtual void CloseSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Removes any stored session data associated with this session. Will only be
    // called for persistent sessions. The CDM must respond by calling either
    // Host::OnResolvePromise() or Host::OnRejectPromise() when the request has
    // been processed.
    virtual void RemoveSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Performs scheduled operation with |context| when the timer fires.
    virtual void TimerExpired(void* context) = 0;

    // Decrypts the |encrypted_buffer|.
    //
    // Returns kSuccess if decryption succeeded, in which case the callee
    // should have filled the |decrypted_buffer| and passed the ownership of
    // |data| in |decrypted_buffer| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kDecryptError if any other error happened.
    // If the return value is not kSuccess, |decrypted_buffer| should be ignored
    // by the caller.
    virtual Status Decrypt(const InputBuffer_2& encrypted_buffer,
      DecryptedBlock* decrypted_buffer) = 0;

    // Initializes the CDM audio decoder with |audio_decoder_config|. This
    // function must be called before DecryptAndDecodeSamples() is called.
    //
    // Returns kSuccess if the |audio_decoder_config| is supported and the CDM
    // audio decoder is successfully initialized.
    // Returns kInitializationError if |audio_decoder_config| is not supported.
    // The CDM may still be able to do Decrypt().
    // Returns kDeferredInitialization if the CDM is not ready to initialize the
    // decoder at this time. Must call Host::OnDeferredInitializationDone() once
    // initialization is complete.
    virtual Status InitializeAudioDecoder(
      const AudioDecoderConfig_2& audio_decoder_config) = 0;

    // Initializes the CDM video decoder with |video_decoder_config|. This
    // function must be called before DecryptAndDecodeFrame() is called.
    //
    // Returns kSuccess if the |video_decoder_config| is supported and the CDM
    // video decoder is successfully initialized.
    // Returns kInitializationError if |video_decoder_config| is not supported.
    // The CDM may still be able to do Decrypt().
    // Returns kDeferredInitialization if the CDM is not ready to initialize the
    // decoder at this time. Must call Host::OnDeferredInitializationDone() once
    // initialization is complete.
    virtual Status InitializeVideoDecoder(
      const VideoDecoderConfig_2& video_decoder_config) = 0;

    // De-initializes the CDM decoder and sets it to an uninitialized state. The
    // caller can initialize the decoder again after this call to re-initialize
    // it. This can be used to reconfigure the decoder if the configuration
    // changes.
    virtual void DeinitializeDecoder(StreamType decoder_type) = 0;

    // Resets the CDM decoder to an initialized clean state. All internal buffers
    // MUST be flushed.
    virtual void ResetDecoder(StreamType decoder_type) = 0;

    // Decrypts the |encrypted_buffer| and decodes the decrypted buffer into a
    // |video_frame|. Upon end-of-stream, the caller should call this function
    // repeatedly with empty |encrypted_buffer| (|data| == NULL) until
    // kNeedMoreData is returned.
    //
    // Returns kSuccess if decryption and decoding both succeeded, in which case
    // the callee will have filled the |video_frame| and passed the ownership of
    // |frame_buffer| in |video_frame| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kNeedMoreData if more data was needed by the decoder to generate
    // a decoded frame (e.g. during initialization and end-of-stream).
    // Returns kDecryptError if any decryption error happened.
    // Returns kDecodeError if any decoding error happened.
    // If the return value is not kSuccess, |video_frame| should be ignored by
    // the caller.
    virtual Status DecryptAndDecodeFrame(const InputBuffer_2& encrypted_buffer,
      VideoFrame* video_frame) = 0;

    // Decrypts the |encrypted_buffer| and decodes the decrypted buffer into
    // |audio_frames|. Upon end-of-stream, the caller should call this function
    // repeatedly with empty |encrypted_buffer| (|data| == NULL) until only empty
    // |audio_frames| is produced.
    //
    // Returns kSuccess if decryption and decoding both succeeded, in which case
    // the callee will have filled |audio_frames| and passed the ownership of
    // |data| in |audio_frames| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kNeedMoreData if more data was needed by the decoder to generate
    // audio samples (e.g. during initialization and end-of-stream).
    // Returns kDecryptError if any decryption error happened.
    // Returns kDecodeError if any decoding error happened.
    // If the return value is not kSuccess, |audio_frames| should be ignored by
    // the caller.
    virtual Status DecryptAndDecodeSamples(const InputBuffer_2& encrypted_buffer,
      AudioFrames* audio_frames) = 0;

    // Called by the host after a platform challenge was initiated via
    // Host::SendPlatformChallenge().
    virtual void OnPlatformChallengeResponse(
      const PlatformChallengeResponse& response) = 0;

    // Called by the host after a call to Host::QueryOutputProtectionStatus(). The
    // |link_mask| is a bit mask of OutputLinkTypes and |output_protection_mask|
    // is a bit mask of OutputProtectionMethods. If |result| is kQueryFailed,
    // then |link_mask| and |output_protection_mask| are undefined and should
    // be ignored.
    virtual void OnQueryOutputProtectionStatus(
      QueryResult result,
      uint32_t link_mask,
      uint32_t output_protection_mask) = 0;

    // Called by the host after a call to Host::RequestStorageId(). If the
    // version of the storage ID requested is available, |storage_id| and
    // |storage_id_size| are set appropriately. |version| will be the same as
    // what was requested, unless 0 (latest) was requested, in which case
    // |version| will be the actual version number for the |storage_id| returned.
    // If the requested version is not available, null/zero will be provided as
    // |storage_id| and |storage_id_size|, respectively, and |version| should be
    // ignored.
    virtual void OnStorageId(uint32_t version,
      const uint8_t* storage_id,
      uint32_t storage_id_size) = 0;

    // Destroys the object in the same context as it was created.
    virtual void Destroy() = 0;

  protected:
    ContentDecryptionModule_10() {}
    virtual ~ContentDecryptionModule_10() {}
  };

  // ----- Note: CDM interface(s) below still in development and not stable! -----

  // ContentDecryptionModule interface that all CDMs need to implement.
  // The interface is versioned for backward compatibility.
  // Note: ContentDecryptionModule implementations must use the allocator
  // provided in CreateCdmInstance() to allocate any Buffer that needs to
  // be passed back to the caller. Implementations must call Buffer::Destroy()
  // when a Buffer is created that will never be returned to the caller.
  class CDM_CLASS_API ContentDecryptionModule_11 {
  public:
    static const int kVersion = 11;
    static const bool kIsStable = false;
    typedef Host_11 Host;

    // Initializes the CDM instance, providing information about permitted
    // functionalities. The CDM must respond by calling Host::OnInitialized()
    // with whether the initialization succeeded. No other calls will be made by
    // the host before Host::OnInitialized() returns.
    // If |allow_distinctive_identifier| is false, messages from the CDM,
    // such as message events, must not contain a Distinctive Identifier,
    // even in an encrypted form.
    // If |allow_persistent_state| is false, the CDM must not attempt to
    // persist state. Calls to CreateFileIO() will fail.
    // If |use_hw_secure_codecs| is true, the CDM must ensure the decryption key
    // and video buffers (compressed and uncompressed) are securely protected by
    // hardware.
    virtual void Initialize(bool allow_distinctive_identifier,
      bool allow_persistent_state,
      bool use_hw_secure_codecs) = 0;

    // Gets the key status if the CDM has a hypothetical key with the |policy|.
    // The CDM must respond by calling either Host::OnResolveKeyStatusPromise()
    // with the result key status or Host::OnRejectPromise() if an unexpected
    // error happened or this method is not supported.
    virtual void GetStatusForPolicy(uint32_t promise_id,
      const Policy& policy) = 0;

    // SetServerCertificate(), CreateSessionAndGenerateRequest(), LoadSession(),
    // UpdateSession(), CloseSession(), and RemoveSession() all accept a
    // |promise_id|, which must be passed to the completion Host method
    // (e.g. Host::OnResolveNewSessionPromise()).

    // Provides a server certificate to be used to encrypt messages to the
    // license server. The CDM must respond by calling either
    // Host::OnResolvePromise() or Host::OnRejectPromise().
    // If the CDM does not support server certificates, the promise should be
    // rejected with kExceptionNotSupportedError. If |server_certificate_data|
    // is empty, reject with kExceptionTypeError. Any other error should be
    // rejected with kExceptionInvalidStateError or kExceptionQuotaExceededError.
    // TODO(crbug.com/796417): Add support for the promise to return true or
    // false, rather than using kExceptionNotSupportedError to mean false.
    virtual void SetServerCertificate(uint32_t promise_id,
      const uint8_t* server_certificate_data,
      uint32_t server_certificate_data_size) = 0;

    // Creates a session given |session_type|, |init_data_type|, and |init_data|.
    // The CDM must respond by calling either Host::OnResolveNewSessionPromise()
    // or Host::OnRejectPromise().
    virtual void CreateSessionAndGenerateRequest(uint32_t promise_id,
      SessionType session_type,
      InitDataType init_data_type,
      const uint8_t* init_data,
      uint32_t init_data_size) = 0;

    // Loads the session of type |session_type| specified by |session_id|.
    // The CDM must respond by calling either Host::OnResolveNewSessionPromise()
    // or Host::OnRejectPromise(). If the session is not found, call
    // Host::OnResolveNewSessionPromise() with session_id = NULL.
    virtual void LoadSession(uint32_t promise_id,
      SessionType session_type,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Updates the session with |response|. The CDM must respond by calling
    // either Host::OnResolvePromise() or Host::OnRejectPromise().
    virtual void UpdateSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size,
      const uint8_t* response,
      uint32_t response_size) = 0;

    // Requests that the CDM close the session. The CDM must respond by calling
    // either Host::OnResolvePromise() or Host::OnRejectPromise() when the request
    // has been processed. This may be before the session is closed. Once the
    // session is closed, Host::OnSessionClosed() must also be called.
    virtual void CloseSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Removes any stored session data associated with this session. Removes all
    // license(s) and key(s) associated with the session, whether they are in
    // memory, persistent store, or both. For persistent session types, other
    // session data (e.g. record of license destruction) will be cleared as
    // defined for each session type once a release message acknowledgment is
    // processed by UpdateSession(). The CDM must respond by calling either
    // Host::OnResolvePromise() or Host::OnRejectPromise() when the request has
    // been processed.
    virtual void RemoveSession(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Performs scheduled operation with |context| when the timer fires.
    virtual void TimerExpired(void* context) = 0;

    // Decrypts the |encrypted_buffer|.
    //
    // Returns kSuccess if decryption succeeded, in which case the callee
    // should have filled the |decrypted_buffer| and passed the ownership of
    // |data| in |decrypted_buffer| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kDecryptError if any other error happened.
    // If the return value is not kSuccess, |decrypted_buffer| should be ignored
    // by the caller.
    virtual Status Decrypt(const InputBuffer_2& encrypted_buffer,
      DecryptedBlock* decrypted_buffer) = 0;

    // Initializes the CDM audio decoder with |audio_decoder_config|. This
    // function must be called before DecryptAndDecodeSamples() is called.
    //
    // Returns kSuccess if the |audio_decoder_config| is supported and the CDM
    // audio decoder is successfully initialized.
    // Returns kInitializationError if |audio_decoder_config| is not supported.
    // The CDM may still be able to do Decrypt().
    // Returns kDeferredInitialization if the CDM is not ready to initialize the
    // decoder at this time. Must call Host::OnDeferredInitializationDone() once
    // initialization is complete.
    virtual Status InitializeAudioDecoder(
      const AudioDecoderConfig_2& audio_decoder_config) = 0;

    // Initializes the CDM video decoder with |video_decoder_config|. This
    // function must be called before DecryptAndDecodeFrame() is called.
    //
    // Returns kSuccess if the |video_decoder_config| is supported and the CDM
    // video decoder is successfully initialized.
    // Returns kInitializationError if |video_decoder_config| is not supported.
    // The CDM may still be able to do Decrypt().
    // Returns kDeferredInitialization if the CDM is not ready to initialize the
    // decoder at this time. Must call Host::OnDeferredInitializationDone() once
    // initialization is complete.
    virtual Status InitializeVideoDecoder(
      const VideoDecoderConfig_3& video_decoder_config) = 0;

    // De-initializes the CDM decoder and sets it to an uninitialized state. The
    // caller can initialize the decoder again after this call to re-initialize
    // it. This can be used to reconfigure the decoder if the configuration
    // changes.
    virtual void DeinitializeDecoder(StreamType decoder_type) = 0;

    // Resets the CDM decoder to an initialized clean state. All internal buffers
    // MUST be flushed.
    virtual void ResetDecoder(StreamType decoder_type) = 0;

    // Decrypts the |encrypted_buffer| and decodes the decrypted buffer into a
    // |video_frame|. Upon end-of-stream, the caller should call this function
    // repeatedly with empty |encrypted_buffer| (|data| == NULL) until
    // kNeedMoreData is returned.
    //
    // Returns kSuccess if decryption and decoding both succeeded, in which case
    // the callee will have filled the |video_frame| and passed the ownership of
    // |frame_buffer| in |video_frame| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kNeedMoreData if more data was needed by the decoder to generate
    // a decoded frame (e.g. during initialization and end-of-stream).
    // Returns kDecryptError if any decryption error happened.
    // Returns kDecodeError if any decoding error happened.
    // If the return value is not kSuccess, |video_frame| should be ignored by
    // the caller.
    virtual Status DecryptAndDecodeFrame(const InputBuffer_2& encrypted_buffer,
      VideoFrame_2* video_frame) = 0;

    // Decrypts the |encrypted_buffer| and decodes the decrypted buffer into
    // |audio_frames|. Upon end-of-stream, the caller should call this function
    // repeatedly with empty |encrypted_buffer| (|data| == NULL) until only empty
    // |audio_frames| is produced.
    //
    // Returns kSuccess if decryption and decoding both succeeded, in which case
    // the callee will have filled |audio_frames| and passed the ownership of
    // |data| in |audio_frames| to the caller.
    // Returns kNoKey if the CDM did not have the necessary decryption key
    // to decrypt.
    // Returns kNeedMoreData if more data was needed by the decoder to generate
    // audio samples (e.g. during initialization and end-of-stream).
    // Returns kDecryptError if any decryption error happened.
    // Returns kDecodeError if any decoding error happened.
    // If the return value is not kSuccess, |audio_frames| should be ignored by
    // the caller.
    virtual Status DecryptAndDecodeSamples(const InputBuffer_2& encrypted_buffer,
      AudioFrames* audio_frames) = 0;

    // Called by the host after a platform challenge was initiated via
    // Host::SendPlatformChallenge().
    virtual void OnPlatformChallengeResponse(
      const PlatformChallengeResponse& response) = 0;

    // Called by the host after a call to Host::QueryOutputProtectionStatus(). The
    // |link_mask| is a bit mask of OutputLinkTypes and |output_protection_mask|
    // is a bit mask of OutputProtectionMethods. If |result| is kQueryFailed,
    // then |link_mask| and |output_protection_mask| are undefined and should
    // be ignored.
    virtual void OnQueryOutputProtectionStatus(
      QueryResult result,
      uint32_t link_mask,
      uint32_t output_protection_mask) = 0;

    // Called by the host after a call to Host::RequestStorageId(). If the
    // version of the storage ID requested is available, |storage_id| and
    // |storage_id_size| are set appropriately. |version| will be the same as
    // what was requested, unless 0 (latest) was requested, in which case
    // |version| will be the actual version number for the |storage_id| returned.
    // If the requested version is not available, null/zero will be provided as
    // |storage_id| and |storage_id_size|, respectively, and |version| should be
    // ignored.
    virtual void OnStorageId(uint32_t version,
      const uint8_t* storage_id,
      uint32_t storage_id_size) = 0;

    // Destroys the object in the same context as it was created.
    virtual void Destroy() = 0;

  protected:
    ContentDecryptionModule_11() {}
    virtual ~ContentDecryptionModule_11() {}
  };

  class CDM_CLASS_API Host_9 {
  public:
    static const int kVersion = 9;

    // Returns a Buffer* containing non-zero members upon success, or NULL on
    // failure. The caller owns the Buffer* after this call. The buffer is not
    // guaranteed to be zero initialized. The capacity of the allocated Buffer
    // is guaranteed to be not less than |capacity|.
    virtual Buffer* Allocate(uint32_t capacity) = 0;

    // Requests the host to call ContentDecryptionModule::TimerFired() |delay_ms|
    // from now with |context|.
    virtual void SetTimer(int64_t delay_ms, void* context) = 0;

    // Returns the current wall time.
    virtual Time GetCurrentWallTime() = 0;

    // Called by the CDM when a key status is available in response to
    // GetStatusForPolicy().
    virtual void OnResolveKeyStatusPromise(uint32_t promise_id,
      KeyStatus key_status) = 0;

    // Called by the CDM when a session is created or loaded and the value for the
    // MediaKeySession's sessionId attribute is available (|session_id|).
    // This must be called before OnSessionMessage() or
    // OnSessionKeysChange() is called for the same session. |session_id_size|
    // should not include null termination.
    // When called in response to LoadSession(), the |session_id| must be the
    // same as the |session_id| passed in LoadSession(), or NULL if the
    // session could not be loaded.
    virtual void OnResolveNewSessionPromise(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Called by the CDM when a session is updated or released.
    virtual void OnResolvePromise(uint32_t promise_id) = 0;

    // Called by the CDM when an error occurs as a result of one of the
    // ContentDecryptionModule calls that accept a |promise_id|.
    // |exception| must be specified. |error_message| and |system_code|
    // are optional. |error_message_size| should not include null termination.
    virtual void OnRejectPromise(uint32_t promise_id,
      Exception exception,
      uint32_t system_code,
      const char* error_message,
      uint32_t error_message_size) = 0;

    // Called by the CDM when it has a message for session |session_id|.
    // Size parameters should not include null termination.
    virtual void OnSessionMessage(const char* session_id,
      uint32_t session_id_size,
      MessageType message_type,
      const char* message,
      uint32_t message_size) = 0;

    // Called by the CDM when there has been a change in keys or their status for
    // session |session_id|. |has_additional_usable_key| should be set if a
    // key is newly usable (e.g. new key available, previously expired key has
    // been renewed, etc.) and the browser should attempt to resume playback.
    // |keys_info| is the list of key IDs for this session along with their
    // current status. |keys_info_count| is the number of entries in |keys_info|.
    // Size parameter for |session_id| should not include null termination.
    virtual void OnSessionKeysChange(const char* session_id,
      uint32_t session_id_size,
      bool has_additional_usable_key,
      const KeyInformation* keys_info,
      uint32_t keys_info_count) = 0;

    // Called by the CDM when there has been a change in the expiration time for
    // session |session_id|. This can happen as the result of an Update() call
    // or some other event. If this happens as a result of a call to Update(),
    // it must be called before resolving the Update() promise. |new_expiry_time|
    // represents the time after which the key(s) in the session will no longer
    // be usable for decryption. It can be 0 if no such time exists or if the
    // license explicitly never expires. Size parameter should not include null
    // termination.
    virtual void OnExpirationChange(const char* session_id,
      uint32_t session_id_size,
      Time new_expiry_time) = 0;

    // Called by the CDM when session |session_id| is closed. Size
    // parameter should not include null termination.
    virtual void OnSessionClosed(const char* session_id,
      uint32_t session_id_size) = 0;

    // The following are optional methods that may not be implemented on all
    // platforms.

    // Sends a platform challenge for the given |service_id|. |challenge| is at
    // most 256 bits of data to be signed. Once the challenge has been completed,
    // the host will call ContentDecryptionModule::OnPlatformChallengeResponse()
    // with the signed challenge response and platform certificate. Size
    // parameters should not include null termination.
    virtual void SendPlatformChallenge(const char* service_id,
      uint32_t service_id_size,
      const char* challenge,
      uint32_t challenge_size) = 0;

    // Attempts to enable output protection (e.g. HDCP) on the display link. The
    // |desired_protection_mask| is a bit mask of OutputProtectionMethods. No
    // status callback is issued, the CDM must call QueryOutputProtectionStatus()
    // periodically to ensure the desired protections are applied.
    virtual void EnableOutputProtection(uint32_t desired_protection_mask) = 0;

    // Requests the current output protection status. Once the host has the status
    // it will call ContentDecryptionModule::OnQueryOutputProtectionStatus().
    virtual void QueryOutputProtectionStatus() = 0;

    // Must be called by the CDM if it returned kDeferredInitialization during
    // InitializeAudioDecoder() or InitializeVideoDecoder().
    virtual void OnDeferredInitializationDone(StreamType stream_type,
      Status decoder_status) = 0;

    // Creates a FileIO object from the host to do file IO operation. Returns NULL
    // if a FileIO object cannot be obtained. Once a valid FileIO object is
    // returned, |client| must be valid until FileIO::Close() is called. The
    // CDM can call this method multiple times to operate on different files.
    virtual FileIO* CreateFileIO(FileIOClient* client) = 0;

    // Requests a specific version of the storage ID. A storage ID is a stable,
    // device specific ID used by the CDM to securely store persistent data. The
    // ID will be returned by the host via ContentDecryptionModule::OnStorageId().
    // If |version| is 0, the latest version will be returned. All |version|s
    // that are greater than or equal to 0x80000000 are reserved for the CDM and
    // should not be supported or returned by the host. The CDM must not expose
    // the ID outside the client device, even in encrypted form.
    virtual void RequestStorageId(uint32_t version) = 0;

  protected:
    Host_9() {}
    virtual ~Host_9() {}
  };

  class CDM_CLASS_API Host_10 {
  public:
    static const int kVersion = 10;

    // Returns a Buffer* containing non-zero members upon success, or NULL on
    // failure. The caller owns the Buffer* after this call. The buffer is not
    // guaranteed to be zero initialized. The capacity of the allocated Buffer
    // is guaranteed to be not less than |capacity|.
    virtual Buffer* Allocate(uint32_t capacity) = 0;

    // Requests the host to call ContentDecryptionModule::TimerFired() |delay_ms|
    // from now with |context|.
    virtual void SetTimer(int64_t delay_ms, void* context) = 0;

    // Returns the current wall time.
    virtual Time GetCurrentWallTime() = 0;

    // Called by the CDM with the result after the CDM instance was initialized.
    virtual void OnInitialized(bool success) = 0;

    // Called by the CDM when a key status is available in response to
    // GetStatusForPolicy().
    virtual void OnResolveKeyStatusPromise(uint32_t promise_id,
      KeyStatus key_status) = 0;

    // Called by the CDM when a session is created or loaded and the value for the
    // MediaKeySession's sessionId attribute is available (|session_id|).
    // This must be called before OnSessionMessage() or
    // OnSessionKeysChange() is called for the same session. |session_id_size|
    // should not include null termination.
    // When called in response to LoadSession(), the |session_id| must be the
    // same as the |session_id| passed in LoadSession(), or NULL if the
    // session could not be loaded.
    virtual void OnResolveNewSessionPromise(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Called by the CDM when a session is updated or released.
    virtual void OnResolvePromise(uint32_t promise_id) = 0;

    // Called by the CDM when an error occurs as a result of one of the
    // ContentDecryptionModule calls that accept a |promise_id|.
    // |exception| must be specified. |error_message| and |system_code|
    // are optional. |error_message_size| should not include null termination.
    virtual void OnRejectPromise(uint32_t promise_id,
      Exception exception,
      uint32_t system_code,
      const char* error_message,
      uint32_t error_message_size) = 0;

    // Called by the CDM when it has a message for session |session_id|.
    // Size parameters should not include null termination.
    virtual void OnSessionMessage(const char* session_id,
      uint32_t session_id_size,
      MessageType message_type,
      const char* message,
      uint32_t message_size) = 0;

    // Called by the CDM when there has been a change in keys or their status for
    // session |session_id|. |has_additional_usable_key| should be set if a
    // key is newly usable (e.g. new key available, previously expired key has
    // been renewed, etc.) and the browser should attempt to resume playback.
    // |keys_info| is the list of key IDs for this session along with their
    // current status. |keys_info_count| is the number of entries in |keys_info|.
    // Size parameter for |session_id| should not include null termination.
    virtual void OnSessionKeysChange(const char* session_id,
      uint32_t session_id_size,
      bool has_additional_usable_key,
      const KeyInformation* keys_info,
      uint32_t keys_info_count) = 0;

    // Called by the CDM when there has been a change in the expiration time for
    // session |session_id|. This can happen as the result of an Update() call
    // or some other event. If this happens as a result of a call to Update(),
    // it must be called before resolving the Update() promise. |new_expiry_time|
    // represents the time after which the key(s) in the session will no longer
    // be usable for decryption. It can be 0 if no such time exists or if the
    // license explicitly never expires. Size parameter should not include null
    // termination.
    virtual void OnExpirationChange(const char* session_id,
      uint32_t session_id_size,
      Time new_expiry_time) = 0;

    // Called by the CDM when session |session_id| is closed. Size
    // parameter should not include null termination.
    virtual void OnSessionClosed(const char* session_id,
      uint32_t session_id_size) = 0;

    // The following are optional methods that may not be implemented on all
    // platforms.

    // Sends a platform challenge for the given |service_id|. |challenge| is at
    // most 256 bits of data to be signed. Once the challenge has been completed,
    // the host will call ContentDecryptionModule::OnPlatformChallengeResponse()
    // with the signed challenge response and platform certificate. Size
    // parameters should not include null termination.
    virtual void SendPlatformChallenge(const char* service_id,
      uint32_t service_id_size,
      const char* challenge,
      uint32_t challenge_size) = 0;

    // Attempts to enable output protection (e.g. HDCP) on the display link. The
    // |desired_protection_mask| is a bit mask of OutputProtectionMethods. No
    // status callback is issued, the CDM must call QueryOutputProtectionStatus()
    // periodically to ensure the desired protections are applied.
    virtual void EnableOutputProtection(uint32_t desired_protection_mask) = 0;

    // Requests the current output protection status. Once the host has the status
    // it will call ContentDecryptionModule::OnQueryOutputProtectionStatus().
    virtual void QueryOutputProtectionStatus() = 0;

    // Must be called by the CDM if it returned kDeferredInitialization during
    // InitializeAudioDecoder() or InitializeVideoDecoder().
    virtual void OnDeferredInitializationDone(StreamType stream_type,
      Status decoder_status) = 0;

    // Creates a FileIO object from the host to do file IO operation. Returns NULL
    // if a FileIO object cannot be obtained. Once a valid FileIO object is
    // returned, |client| must be valid until FileIO::Close() is called. The
    // CDM can call this method multiple times to operate on different files.
    virtual FileIO* CreateFileIO(FileIOClient* client) = 0;

    // Requests a specific version of the storage ID. A storage ID is a stable,
    // device specific ID used by the CDM to securely store persistent data. The
    // ID will be returned by the host via ContentDecryptionModule::OnStorageId().
    // If |version| is 0, the latest version will be returned. All |version|s
    // that are greater than or equal to 0x80000000 are reserved for the CDM and
    // should not be supported or returned by the host. The CDM must not expose
    // the ID outside the client device, even in encrypted form.
    virtual void RequestStorageId(uint32_t version) = 0;

  protected:
    Host_10() {}
    virtual ~Host_10() {}
  };

  class CDM_CLASS_API Host_11 {
  public:
    static const int kVersion = 11;

    // Returns a Buffer* containing non-zero members upon success, or NULL on
    // failure. The caller owns the Buffer* after this call. The buffer is not
    // guaranteed to be zero initialized. The capacity of the allocated Buffer
    // is guaranteed to be not less than |capacity|.
    virtual Buffer* Allocate(uint32_t capacity) = 0;

    // Requests the host to call ContentDecryptionModule::TimerFired() |delay_ms|
    // from now with |context|.
    virtual void SetTimer(int64_t delay_ms, void* context) = 0;

    // Returns the current wall time.
    virtual Time GetCurrentWallTime() = 0;

    // Called by the CDM with the result after the CDM instance was initialized.
    virtual void OnInitialized(bool success) = 0;

    // Called by the CDM when a key status is available in response to
    // GetStatusForPolicy().
    virtual void OnResolveKeyStatusPromise(uint32_t promise_id,
      KeyStatus key_status) = 0;

    // Called by the CDM when a session is created or loaded and the value for the
    // MediaKeySession's sessionId attribute is available (|session_id|).
    // This must be called before OnSessionMessage() or
    // OnSessionKeysChange() is called for the same session. |session_id_size|
    // should not include null termination.
    // When called in response to LoadSession(), the |session_id| must be the
    // same as the |session_id| passed in LoadSession(), or NULL if the
    // session could not be loaded.
    virtual void OnResolveNewSessionPromise(uint32_t promise_id,
      const char* session_id,
      uint32_t session_id_size) = 0;

    // Called by the CDM when a session is updated or released.
    virtual void OnResolvePromise(uint32_t promise_id) = 0;

    // Called by the CDM when an error occurs as a result of one of the
    // ContentDecryptionModule calls that accept a |promise_id|.
    // |exception| must be specified. |error_message| and |system_code|
    // are optional. |error_message_size| should not include null termination.
    virtual void OnRejectPromise(uint32_t promise_id,
      Exception exception,
      uint32_t system_code,
      const char* error_message,
      uint32_t error_message_size) = 0;

    // Called by the CDM when it has a message for session |session_id|.
    // Size parameters should not include null termination.
    virtual void OnSessionMessage(const char* session_id,
      uint32_t session_id_size,
      MessageType message_type,
      const char* message,
      uint32_t message_size) = 0;

    // Called by the CDM when there has been a change in keys or their status for
    // session |session_id|. |has_additional_usable_key| should be set if a
    // key is newly usable (e.g. new key available, previously expired key has
    // been renewed, etc.) and the browser should attempt to resume playback.
    // |keys_info| is the list of key IDs for this session along with their
    // current status. |keys_info_count| is the number of entries in |keys_info|.
    // Size parameter for |session_id| should not include null termination.
    virtual void OnSessionKeysChange(const char* session_id,
      uint32_t session_id_size,
      bool has_additional_usable_key,
      const KeyInformation* keys_info,
      uint32_t keys_info_count) = 0;

    // Called by the CDM when there has been a change in the expiration time for
    // session |session_id|. This can happen as the result of an Update() call
    // or some other event. If this happens as a result of a call to Update(),
    // it must be called before resolving the Update() promise. |new_expiry_time|
    // represents the time after which the key(s) in the session will no longer
    // be usable for decryption. It can be 0 if no such time exists or if the
    // license explicitly never expires. Size parameter should not include null
    // termination.
    virtual void OnExpirationChange(const char* session_id,
      uint32_t session_id_size,
      Time new_expiry_time) = 0;

    // Called by the CDM when session |session_id| is closed. Size
    // parameter should not include null termination.
    virtual void OnSessionClosed(const char* session_id,
      uint32_t session_id_size) = 0;

    // The following are optional methods that may not be implemented on all
    // platforms.

    // Sends a platform challenge for the given |service_id|. |challenge| is at
    // most 256 bits of data to be signed. Once the challenge has been completed,
    // the host will call ContentDecryptionModule::OnPlatformChallengeResponse()
    // with the signed challenge response and platform certificate. Size
    // parameters should not include null termination.
    virtual void SendPlatformChallenge(const char* service_id,
      uint32_t service_id_size,
      const char* challenge,
      uint32_t challenge_size) = 0;

    // Attempts to enable output protection (e.g. HDCP) on the display link. The
    // |desired_protection_mask| is a bit mask of OutputProtectionMethods. No
    // status callback is issued, the CDM must call QueryOutputProtectionStatus()
    // periodically to ensure the desired protections are applied.
    virtual void EnableOutputProtection(uint32_t desired_protection_mask) = 0;

    // Requests the current output protection status. Once the host has the status
    // it will call ContentDecryptionModule::OnQueryOutputProtectionStatus().
    virtual void QueryOutputProtectionStatus() = 0;

    // Must be called by the CDM if it returned kDeferredInitialization during
    // InitializeAudioDecoder() or InitializeVideoDecoder().
    virtual void OnDeferredInitializationDone(StreamType stream_type,
      Status decoder_status) = 0;

    // Creates a FileIO object from the host to do file IO operation. Returns NULL
    // if a FileIO object cannot be obtained. Once a valid FileIO object is
    // returned, |client| must be valid until FileIO::Close() is called. The
    // CDM can call this method multiple times to operate on different files.
    virtual FileIO* CreateFileIO(FileIOClient* client) = 0;

    // Requests a CdmProxy that proxies part of CDM functionalities to a different
    // entity, e.g. a hardware CDM module. A CDM instance can have at most one
    // CdmProxy throughout its lifetime, which must be requested and initialized
    // during CDM instance initialization time, i.e. in or after CDM::Initialize()
    // and before OnInitialized() is called, to ensure proper connection of the
    // CdmProxy and the media player (e.g. hardware decoder). The CdmProxy is
    // owned by the host and is guaranteed to be valid throughout the CDM
    // instance's lifetime. The CDM must ensure that the |client| remain valid
    // before the CDM instance is destroyed. Returns null if CdmProxy is not
    // supported, called before CDM::Initialize(), RequestCdmProxy() is called
    // more than once, or called after the CDM instance has been initialized.
    virtual CdmProxy* RequestCdmProxy(CdmProxyClient* client) = 0;

    // Requests a specific version of the storage ID. A storage ID is a stable,
    // device specific ID used by the CDM to securely store persistent data. The
    // ID will be returned by the host via ContentDecryptionModule::OnStorageId().
    // If |version| is 0, the latest version will be returned. All |version|s
    // that are greater than or equal to 0x80000000 are reserved for the CDM and
    // should not be supported or returned by the host. The CDM must not expose
    // the ID outside the client device, even in encrypted form.
    virtual void RequestStorageId(uint32_t version) = 0;

  protected:
    Host_11() {}
    virtual ~Host_11() {}
  };

}  // namespace cdm

#endif  // CDM_CONTENT_DECRYPTION_MODULE_H_